1 /* Copyright JS Foundation and other contributors, http://js.foundation
2 *
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16 #include "ecma-gc.h"
17 #include "ecma-globals.h"
18 #include "ecma-helpers.h"
19 #include "ecma-lcache.h"
20 #include "jcontext.h"
21
22 /** \addtogroup ecma ECMA
23 * @{
24 *
25 * \addtogroup ecmalcache Property lookup cache
26 * @{
27 */
28
29 #if ENABLED (JERRY_LCACHE)
30
31 /**
32 * Bitshift index for calculating hash.
33 */
34 #if ENABLED (JERRY_CPOINTER_32_BIT)
35 #define ECMA_LCACHE_HASH_BITSHIFT_INDEX (2 * JMEM_ALIGNMENT_LOG)
36 #else /* !ENABLED (JERRY_CPOINTER_32_BIT) */
37 #define ECMA_LCACHE_HASH_BITSHIFT_INDEX 0
38 #endif /* ENABLED (JERRY_CPOINTER_32_BIT) */
39
40 /**
41 * Mask for hash bits
42 */
43 #define ECMA_LCACHE_HASH_MASK ((ECMA_LCACHE_HASH_ROWS_COUNT - 1) << ECMA_LCACHE_HASH_BITSHIFT_INDEX)
44
45 /**
46 * Bitshift index for creating property identifier
47 */
48 #define ECMA_LCACHE_HASH_ENTRY_ID_SHIFT (8 * sizeof (jmem_cpointer_t))
49
50 /**
51 * Create property identifier
52 */
53 #define ECMA_LCACHE_CREATE_ID(object_cp, name_cp) \
54 (((ecma_lcache_hash_entry_id_t) (object_cp) << ECMA_LCACHE_HASH_ENTRY_ID_SHIFT) | (name_cp))
55
56 /**
57 * Invalidate specified LCache entry
58 */
59 static inline void JERRY_ATTR_ALWAYS_INLINE
ecma_lcache_invalidate_entry(ecma_lcache_hash_entry_t * entry_p)60 ecma_lcache_invalidate_entry (ecma_lcache_hash_entry_t *entry_p) /**< entry to invalidate */
61 {
62 JERRY_ASSERT (entry_p != NULL);
63 JERRY_ASSERT (entry_p->id != 0);
64 JERRY_ASSERT (entry_p->prop_p != NULL);
65
66 entry_p->id = 0;
67 ecma_set_property_lcached (entry_p->prop_p, false);
68 } /* ecma_lcache_invalidate_entry */
69
70 /**
71 * Compute the row index of object / property name pair
72 *
73 * @return row index
74 */
75 static inline size_t JERRY_ATTR_ALWAYS_INLINE
ecma_lcache_row_index(jmem_cpointer_t object_cp,jmem_cpointer_t name_cp)76 ecma_lcache_row_index (jmem_cpointer_t object_cp, /**< compressed pointer to object */
77 jmem_cpointer_t name_cp) /**< compressed pointer to property name */
78 {
79 /* Randomize the property name with the object pointer using a xor operation,
80 * so properties of different objects with the same name can be cached effectively. */
81 return (size_t) (((name_cp ^ object_cp) & ECMA_LCACHE_HASH_MASK) >> ECMA_LCACHE_HASH_BITSHIFT_INDEX);
82 } /* ecma_lcache_row_index */
83
84 /**
85 * Insert an entry into LCache
86 */
87 void
ecma_lcache_insert(const ecma_object_t * object_p,const jmem_cpointer_t name_cp,ecma_property_t * prop_p)88 ecma_lcache_insert (const ecma_object_t *object_p, /**< object */
89 const jmem_cpointer_t name_cp, /**< property name */
90 ecma_property_t *prop_p) /**< property */
91 {
92 JERRY_ASSERT (object_p != NULL);
93 JERRY_ASSERT (prop_p != NULL && !ecma_is_property_lcached (prop_p));
94 JERRY_ASSERT (ECMA_PROPERTY_GET_TYPE (*prop_p) == ECMA_PROPERTY_TYPE_NAMEDDATA
95 || ECMA_PROPERTY_GET_TYPE (*prop_p) == ECMA_PROPERTY_TYPE_NAMEDACCESSOR
96 || ECMA_PROPERTY_GET_TYPE (*prop_p) == ECMA_PROPERTY_TYPE_INTERNAL);
97
98 jmem_cpointer_t object_cp;
99
100 ECMA_SET_NON_NULL_POINTER (object_cp, object_p);
101
102 size_t row_index = ecma_lcache_row_index (object_cp, name_cp);
103 ecma_lcache_hash_entry_t *entry_p = JERRY_CONTEXT (lcache) [row_index];
104 ecma_lcache_hash_entry_t *entry_end_p = entry_p + ECMA_LCACHE_HASH_ROW_LENGTH;
105
106 do
107 {
108 if (entry_p->id == 0)
109 {
110 goto insert;
111 }
112
113 entry_p++;
114 }
115 while (entry_p < entry_end_p);
116
117 /* Invalidate the last entry. */
118 ecma_lcache_invalidate_entry (--entry_p);
119
120 /* Shift other entries towards the end. */
121 for (uint32_t i = 0; i < ECMA_LCACHE_HASH_ROW_LENGTH - 1; i++)
122 {
123 entry_p->id = entry_p[-1].id;
124 entry_p->prop_p = entry_p[-1].prop_p;
125 entry_p--;
126 }
127
128 insert:
129 entry_p->prop_p = prop_p;
130 entry_p->id = ECMA_LCACHE_CREATE_ID (object_cp, name_cp);
131
132 ecma_set_property_lcached (entry_p->prop_p, true);
133 } /* ecma_lcache_insert */
134
135 /**
136 * Lookup property in the LCache
137 *
138 * @return a pointer to an ecma_property_t if the lookup is successful
139 * NULL otherwise
140 */
141 inline ecma_property_t * JERRY_ATTR_ALWAYS_INLINE
ecma_lcache_lookup(const ecma_object_t * object_p,const ecma_string_t * prop_name_p)142 ecma_lcache_lookup (const ecma_object_t *object_p, /**< object */
143 const ecma_string_t *prop_name_p) /**< property's name */
144 {
145 JERRY_ASSERT (object_p != NULL);
146 JERRY_ASSERT (prop_name_p != NULL);
147
148 jmem_cpointer_t object_cp;
149 ECMA_SET_NON_NULL_POINTER (object_cp, object_p);
150
151 ecma_property_t prop_name_type = ECMA_DIRECT_STRING_PTR;
152 jmem_cpointer_t prop_name_cp;
153
154 if (JERRY_UNLIKELY (ECMA_IS_DIRECT_STRING (prop_name_p)))
155 {
156 prop_name_type = (ecma_property_t) ECMA_GET_DIRECT_STRING_TYPE (prop_name_p);
157 prop_name_cp = (jmem_cpointer_t) ECMA_GET_DIRECT_STRING_VALUE (prop_name_p);
158 }
159 else
160 {
161 ECMA_SET_NON_NULL_POINTER (prop_name_cp, prop_name_p);
162 }
163
164 size_t row_index = ecma_lcache_row_index (object_cp, prop_name_cp);
165
166 ecma_lcache_hash_entry_t *entry_p = JERRY_CONTEXT (lcache) [row_index];
167 ecma_lcache_hash_entry_t *entry_end_p = entry_p + ECMA_LCACHE_HASH_ROW_LENGTH;
168 ecma_lcache_hash_entry_id_t id = ECMA_LCACHE_CREATE_ID (object_cp, prop_name_cp);
169
170 do
171 {
172 if (entry_p->id == id && JERRY_LIKELY (ECMA_PROPERTY_GET_NAME_TYPE (*entry_p->prop_p) == prop_name_type))
173 {
174 JERRY_ASSERT (entry_p->prop_p != NULL && ecma_is_property_lcached (entry_p->prop_p));
175 return entry_p->prop_p;
176 }
177 entry_p++;
178 }
179 while (entry_p < entry_end_p);
180
181 return NULL;
182 } /* ecma_lcache_lookup */
183
184 /**
185 * Invalidate LCache entries associated with given object and property name / property
186 */
187 void
ecma_lcache_invalidate(const ecma_object_t * object_p,const jmem_cpointer_t name_cp,ecma_property_t * prop_p)188 ecma_lcache_invalidate (const ecma_object_t *object_p, /**< object */
189 const jmem_cpointer_t name_cp, /**< property name */
190 ecma_property_t *prop_p) /**< property */
191 {
192 JERRY_ASSERT (object_p != NULL);
193 JERRY_ASSERT (prop_p != NULL && ecma_is_property_lcached (prop_p));
194 JERRY_ASSERT (ECMA_PROPERTY_GET_TYPE (*prop_p) == ECMA_PROPERTY_TYPE_NAMEDDATA
195 || ECMA_PROPERTY_GET_TYPE (*prop_p) == ECMA_PROPERTY_TYPE_NAMEDACCESSOR
196 || ECMA_PROPERTY_GET_TYPE (*prop_p) == ECMA_PROPERTY_TYPE_INTERNAL);
197
198 jmem_cpointer_t object_cp;
199 ECMA_SET_NON_NULL_POINTER (object_cp, object_p);
200
201 size_t row_index = ecma_lcache_row_index (object_cp, name_cp);
202 ecma_lcache_hash_entry_t *entry_p = JERRY_CONTEXT (lcache) [row_index];
203
204 while (true)
205 {
206 /* The property must be present. */
207 JERRY_ASSERT (entry_p - JERRY_CONTEXT (lcache) [row_index] < ECMA_LCACHE_HASH_ROW_LENGTH);
208
209 if (entry_p->id != 0 && entry_p->prop_p == prop_p)
210 {
211 JERRY_ASSERT (entry_p->id == ECMA_LCACHE_CREATE_ID (object_cp, name_cp));
212
213 ecma_lcache_invalidate_entry (entry_p);
214 return;
215 }
216 entry_p++;
217 }
218 } /* ecma_lcache_invalidate */
219
220 #endif /* ENABLED (JERRY_LCACHE) */
221
222 /**
223 * @}
224 * @}
225 */
226